In order to suppress a synchronism loss of power generators at the time of a system accident, there is a scheme of creating an analysis system model based on collected information on a power system, and calculating a transient stability under an accident condition generated after an occurrence of the system accident, thereby determining whether the synchronism loss of the power generator is occurred or not. According to this scheme, a target power generator (a power-control target generator) target to be disconnected that is necessary to suppress a synchronism loss is determined, and then the power-control target generator is disconnected from the power system, thereby making the power system stable.
According to the above-explained scheme of stabilizing the power system, in order to suppress a synchronism loss of power generators at the time of a system accident, some power generators are disconnected from the power system. However, it often takes a time to connect again the disconnected power generator with the power system. Therefore, it is desirable to avoid the disconnection of the power generator as much as possible. Accordingly, the target generators to be controlled are selected to be necessary minimum.
In recent years, an introduction of renewable energy power generators like solar power generators has been advanced. Some renewable energy power generators are connected with a power system through an inverter or a power electronics device so-called a power conditioner, and those can control the operation and the shutdown at a fast speed.
Under such a technical background, it can be thought that the renewable energy power generators may be shutdown instead of disconnecting a power generator to stabilize the power system, or to reduce the number of power-control target generators necessary for the stabilization of the power system. However, there is no actual case in which a renewable energy power generator is subjected to a shutdown.